Sulfophenoxy malonate compounds and cationic dyeable copolyesters containing same

ABSTRACT

Sulfophenoxy malonate compounds and copolyester resins utilizing said malonate compounds comprising the condensation product of (a) an aromatic dicarboxylic acid or its lower alkyl diester, (b) an aliphatic glycol, and (c) a minor amount of a substituted acid or ester thereof represented by the formula:   WHEREIN R1 and R2 are both hydrogen or lower alkyl radicals, R3 is hydrogen or a lower alkyl radical, and M is a metal.

United States Patent John A. Price Swarthmore;

Mary J. Stewart, Riddlewood, both of Pa. [2| I Appl. No. 37,838

[72) Inventors [22] Filed May l5, 1970 [45) Patented Nov. 30, 197i [73 1Assignee FMC Corporation Philadelphia, Pa.

Continuation-impart of application Ser. No. 867,375, Oct. 17, 1969. Thisapplication May 15, 1970, Ser. No. 37,838

[54] SULFOP'HENOXY MALONATE COMPOUNDS AND CATIONIC DYEABLE COPOLYESTERS[5 6] Relerences Cited UNITED STATES PATENTS 1/1962 Griffing et al3.238.]80 3/l966 Wiloth 3,313.778 4/1967 Sakuraietal.

Primary Examiner-William H. Short Assistant Examiner-L. L. Lee

Anorneys-Thomas R. O'Malley- George F. Mueller and Charles A. HaaseABSTRACT: Sulfophenoxy malonate compounds and copolyester resinsutilizing said malonate compounds comprising the condensation product of(a) an aromatic dicarboxylic acid or its lower alkyl diester, (b) analiphatic glycol. and (c) a minor amount of a substituted acid or esterthereof represented by the formula ,7 7 H59 wherein R and R are bothhydrogen or lower alkyl radicals, R is hydrogen or a lower alkylradical, and M is a metal.

SULFOPHENOXY MALONATE COMPOUNDS AND CA'IIONIC DYEABLE COPOLYES'I'ERSCONTAINING SAME This application is a continuation-in-part of our US.application Ser. No. 867,375, filed Oct. I7, 1969.

This invention relates to highly polymeric linear copolyester resinswhich have improved dyeability. More particularly, the present inventionrelates to novel copolyester resins which can be formed into filaments,films, or other shaped articles and which can be readily dyed with basictype dyes. The term basic dye" is used herein to denote cationic organicdyes such as, for example, those containing sulfonium, oxonium, orquaternary ammonium functional groups.

Many types of random copolyesters have been described in the prior artand they can be prepared by various well-known processes. For example,copolyester resins can be prepared by a direct esterification andpolycondensation process or by a transesterification andpolycondensation process. In the case of the direct esterficationmethod, the reactants used consist of suitable dicarboxylic acids and.diols; whereas, in a transesterification method, lower alkyl diesters ofsuitable dicarboxylic acids and diols are used as the initial reactants.

A copolyester resin, such as those of the present invention, which aresuitable for filamentand film-fonning purposes should have relativelyhigh-intrinsic viscosity, preferably not less than about 0.60 (asdetermined in a 60 percent phenol- 40 percent tetrachloroethanesolution, wt./wt., at 30 C.), a carboxyl content value of below about 50equivalents per million grams eq./l gr. or meq./kg.), a suitablyhigh-melting point and also exhibit a relatively colorless or whitecolor. Additionally, especially for filament-forming purposes, it isvery desirable and necessary in many instances that the polyester resinbe dyeable with cationic or basic dyes.

It is an object of this invention to provide novel highly polymericsaturated copolyester resins.

It is another object of this invention to provide highly polymericlinear copolyester resins, which have physical and chemical propertieswhich make them particularly well-suited for filamentand film-formingpurposes.

It is a further object of the present invention to provide highlypolymeric copolyester resins which are readily dyeable with basic typedyes.

These and other objects are accomplished in accordance with the presentinvention by providing a highly polymeric copolyester resin comprisingthe condensation polymerization product of (a) an aromatic dicarboxylicacid or its lower alkyl diester, (b) an aliphatic glycol, and (c) aminor amount of a substituted acid or ester thereof represented by theformula:

wherein R and R, are both hydrogen or lower alkyl radicals 0 containingfrom one to four carbon atoms, R is hydrogen or a lower alkyl radicalcontaining from one to six carbon atoms, and M is a metal.

The random copolyester resins of the present invention can be preparedas stated above by either a transesterification or direct esterificationprocess. In either instance, all the reactants can be initially combinedand charged into a suitable reactor wherein one of the subject processesis carried out.

For illustration purposes. the general structure of several preferredembodiments of the present invention can be represented by combining thefollowing segments designated (1) and (2) or by combining segments (1),(2), and (3). In either of these examples, a minor percentage of 1,3-propanediol,2,2-diethyll ,3 -pmpanediol,2,2-dimethyll ,4-butanediol, 2)and (3) would use presentin the copolyester resin chain.

wherein z is a positive integer of from two to six, R is hydrogen or analkyl radical having from one to six carbon atoms, lvijs a metal, A is adivalentsaturated aromatic radical, a and b represent positive integersof from one to three, and R. and R represent lower alkyl radicalscontaining from one to six carbon atoms.

It has been determined that a preferred group of copolyester resinsofthe present invention are those containing from about 0.5 to 10 molepercent of secondary segments" represented by (2) above and from about99.5 to mole percent of primary segments represented by (I) above. Otherpreferred embodiments contain, in addition to the 0.5 to 10 mole percentof the "secondary segments," from 0.5 to 10 mole percent of segmentsrepresented by (3) above. Obviously, the copolyester resins of thepresent invention are not limited by such preferred concentrations.Copolyester resins containing smaller or greater concentrations ofsegments (2) and (3) above can also be prepared depending on thephysical and chemical properties desired along with depth of dyeabilityneeded.

The aliphatic glycols which can be employed in conjunction with theterephthalic acid or diesters thereof used to prepare the primarysegments are those having the formula: HO(CH,),OH, wherein z is apositive integer of from two to six and cycloaliphatic glycols such as1,4-cyclohexane dimethanol. Among the alkylene glycols that can be usedto prepare the primary segments" are, for example, ethylene glycol,1,3-propylene glycol, and l,6-hexylene glycol.

The saturated aromatic dibasic acid used as the acid component of theprimary segments" is terephthalic acid. Obviously, if thetransesterification method is utilized to prepare the subjectcopolyesters, a corresponding lower alkyl diester of such a dibasic acidwould be used instead of free acid. The alkyl groups of such a dialkylester can contain from one to four carbon atoms.

The ester segments (2) above designated "secondary segments" are derivedfrom an alkylene glycol having the formula: HO(CH ),OH, as describedabove wherein z is from two to six or a cycloaliphatic glycol such asl,4-cyclohexane dimethanol.

The substituted acid or esters thereof which are used to preparesegments (2) above can be any of those coming within the bounds of theformula:

wherein R, and R, are both hydrogen or lower alkyl radicals containingfrom one to four carbon atoms, R, is hydrogen or a lower alkyl radicalcontaining from one to six carbon atoms, and M represents any suitablemetallic element preferably,

however, because of ease of preparation, M is generally selected fromthe group consisting of the alkaline earth metals and alkali metals. Forexample, among the compounds that can be used are the metallic salts ofdiethyl 2-methyl-2-(p-sulfophenoxy) malonate, dimethylZ-(p-sulfophenoxy) malonate, dibutyl 2-propyl-2-(p-sulfophenoxy)malonate, dimethyl 2- pentyl2-(p-sulfophenoxy) malonate, dibutyl2-hexyl-2-(p-sulfophenoxy) malonate, or their corresponding dicarboxylicacids and/or suitable mixtures thereof.

Specifically, the above defined sulfophenoxy malonate compounds can bereadily prepared from p-hydroxybenzenesulfonic acid by first titratingsame in a water solution with a solution of an alkali metal or alkalineearth metal at room temperature in order to obtain a correspondingdimetallic salt thereof. Then filter the resulting solution andevaporate the obtained filtrate to dryness at reduced pressure. Theconcentrate obtained is then slurried in acetone and filtered. Theprecipitate is then dried in vacuo at about l to 120 C. for 3 days toyield the corresponding dimetallic salt of p-hydroxybenzenesulfonicacid. For example, the above defined solutions of alkali and alkalineearth metals can be prepared from sodium hydroxide, calcium oxide,lithium hydroxide, potassium hydroxide or barium oxide.

The above-prepared (l) p-hydroxybenzenesulfonic acid, dimetallic salt,and (11) a dialkyl 2-ha1o-2-alkyl malonate compound at a mole ratio ofabout 1: 1.2 respectively are placed in a large excess ofdimethylformamide and heated at about 90 C. for 4 hours, then kept atroom temperature overnight. [Alkyl group (1) can contain from one tofour carbon atoms, alkyl groups (3) from one to six carbon atoms andhalo group (2) can be chlorine bromine or iodine]. The resultingsolution is then evaporated to dryness in vacuo and the concentrateobtained is recrystallized in boiling ethanol. The product obtained willbe a dialkyl 2-alkyl-2-(p-sulfophenoxy) malonate, metallic salt. If itis desired to prepare a dialkyl 2-(p-sulfophenoxy) malonate, metallicsalt, then obviously the reactant used (11 above) would be a dialkyl2-halo-malonate rather than the 2-alkyl substituted malonate.

If a diacid counterpart of the above described sulfophenoxy malonatediesters is desired, it can be prepared from the above describeddiesters by using standard saponification techniques known to thoseskilled in the present art. Among the malonate reactants (11) that canbe used to prepare the subject sulfonated monomers are dimethyl2-bromo-2-ethylmalonate, dibutyl 2-chloro-2-propylmalonate, dimethyl2-bromo- 2methylmalonate, diethyl 2-bromomalonate, dipropyl 2-chloromalonate, dimethyl Z-bromomalonate.

For a more specific illustration, diethyl 2-methyl-2-(p-sulfophenoxy)malonate, sodium salt, can be prepared as follows:

EXAMPLE A (a) A solution of 236 grams (1.0 mole) of a 65 percent aqueousp-hydroxybenzenesulfonic acid was titrated with a 4N sodium hydroxidesolution to a pH of 10.5. The resulting solution was filtered and thenevaporated to dryness at reduced pressure. The residue was then slurriedin acetone and filtered. The precipitate obtained was dried in vacuo at1 10 to 120 C. for 3 days to yield 236 grams of the disodium salt ofp-hydroxybenzenesulfonic acid. (b) A mixture of 54.5 grams (0.25 mole)of p-hydroxybenzenesulfonic acid, disodium salt, and 111 grams (0.3 moleof diethyl 2-bromo-2- methylmalonate in 500 ml. of dry dimethylformamidewas heated at about 90 C. for about 4 hours and then kept at roomtemperature overnight. The resulting solution was evaporated to drynessin vacuo. The residue was then slurried in boiling ethanol and filteredto give a white precipitate on cooling. The resulting compound wasidentified as diethyl 2- methyl-2-(p-sulfophenoxy) malonate, sodiumsalt.

The dicarboxylic acid counterpart of the above-prepared diethyl2-methyl-2-(psull'ophenoxy) malonate, sodium salt, is prepared asfollows: Take 21.8 grams of diethyl 2-methyl-2 (p-sulfophenoxy)malonate, sodium salt, and mix with a solution of 28 grams of potassiumhydroxide dissolved in 150 ml.

diethylene glycol. Reflux 4 hours. Cool to room temperature and acidifyto pH 1.0 using dilute hydrochloric acid. The resulting precipitate isthen filtered off and dried in vacuo to give2-methyl-2-(p-sodiumsulfophenoxy) malonic acid.

The ester segments designated (3) above can be prepared from anygem-dialkyl glycol coming within the formula:

( F-(CHDbOIl where a and b represent positive integers of from one tothree and R and R represent lower alkyl radicals containing from one tosix carbon atoms. Among those which can be used. for example, are3,3-dipropyl-l,5-pentanediol, 2,2-dimethyl-l,3- propanediol,2,2-diethyl-1,3-propanediol, 2,2-dimethyl-1,4- butanediol,3,3-dimethyl-1,5-pentanediol, 2-ethyl-2-methyl- 1,3-propanediol, and2,2-dibutyl-1,3-propanediol.

Any suitable saturated aromatic dicarboxylic acid known in the polyesterart can be used to prepare ester segments (3) above. The term saturatedaromatic dicarboxylic acid" is used herein to define any aromaticdicarboxylic acid which does not contain any ethylenic unsaturation.Among the dibasic acids which can be used are terephthalic acid,isophthalic acid, 4,4'-bibenzoic acid, p,p-dicarboxydiphenyl propane,4,4'-diphenylsulfone dicarboxylic acid. and 2,6- naphthalenedicarboxylic acid or suitable lower dialkyl esters thereof and anycombination thereof.

1n the case of the ester-interchange or transesterification method, amole ratio of diol to suitable diester of from about 1:1 to about 15:1may be used, but preferably from about 1.5:] to about 26:1. Thetransesterification reaction is generally carried out at atmosphericpressure in an inert atmosphere such as nitrogen. initially at atemperature range from about C. to about 250 C., but preferably fromabout C. to 200 C. in the presence'of a transesterification catalyst. Analkyl alcohol corresponding to the dialkyl ester of the dicarboxylicacid used is evolved and continuously removed by distillation. After areaction period of l to 2 hours, the temperature of the reaction mixtureis raised from about 200 C. to about 230 C. for approximately 1 to 3hours in order to complete the reaction, form the desired polyesterprepolymer and distill off any excess diol which is present.

Any of the well-known and suitable transesterification orester-interchange catalysts, for example, lithium amide, lithiumhydride, or zinc acetate can be used to catalyze the presenttransesterification reaction. In most instances, the transesterificationcatalyst is used in concentrations ranging from 0.01 percent to about0.20 percent based on the weight of the dialkyl ester of thedicarboxylic acid used in the initial reaction mixture.

Alternatively, the preparation of the subject prepolymers or polyesterresins can be achieved via the direct esterification method. in the caseof the direct esterification method, a mole ratio of diol todicarboxylic acid of from about 1.2:1 to about 15:1, but preferably fromabout 1.5:] to about 2.621 is used. The initial steps of the directesterification reaction are generally carried out at temperaturesranging from about 180 C. to about 280 C. in the absence of anoxygen-containing atmosphere at atmospheric or elevated pressure forabout 2 to 4 hours to form the desired polyester prepolymer. Forexample, the reaction may be carried out in an atmosphere of nitrogen.

Any of the well-known and suitable first-stage direct esterificationcatalytic additives can be used in the preparation of the presentcopolyester resins via the direct esterification method. For example,triethylamine or calcium acetate may be used. The first-stage catalyticadditives are generally employed at concentrations ranging from about5X10" mole to about 5X10 mole of catalytic additive per mole ofdicarboxylic acid used in the initial reaction mixture.

The polycondensation of the prepolymers prepared by one of the aboveprocesses is accomplished by adding a suitable polycondensation catalystto the polyester prepolymer or prepolymers as defined above and heatingthe blend thereof under reduced pressures of within the range of about0.05 mm. to 20 mm. of mercury while under agitation at a temperature ofabout 260 C. to 325 C. for from 2 to 4 hours. Any suitablepolycondensationcatalyst can be used, for example, antimony oxalate.antimony trioxide, or disodium lead ethylene diamine tetra-acetate.

Several preferred embodiments of the resins of the present invention arefurther illustrated by the following examples.

EXAMPLE 1 One hundred forty six grams'of dimethyl terephthalate, 9.4grams of the sodium salt of diethyl 2-methyl-2-(p-sulfophenoxy)malonate, 99 mls. ethylene glycol, and 0.06 grams of lithium hydride wascharged into a reaction vessel equipped witha nitrogen inlet, adistilling arm, heating means and stirring means. The reaction mixturewas agitated and heated at atmospheric pressure to about l98 C. under anitrogen blanket with stirring. The reaction mixture was held at aboutl98 C. for about 2 hours during which time methyl alcohol and other byproducts were distilled off. Then the temperature of the reactionmixture was allowed to rise to about 230 C. over a period of about 1 todistill off any remaining byproducts and thereby form the desiredcopolyester prepolymer. The prepolymer was then allowed to cool under anatmosphere of nitrogen.

EXAMPLE ll Fifty grams of the prepolymer product of example I was mixedwith 0.02 grams of antimony trioxide and placed in a reaction vessel.This reaction mixture was then heated at about 280 C. under reducedpressure of about 0.1 mm. of mercury while under agitation for about 2hours to bring about the polycondensation of the prepolymer andformation of a copolyester resin. The copolyester resin product formedhad an intrinsic viscosity of 0.61, a diethylene glycol content of 0.93weight percent, a carboxyl content value of 14 meg/kg, and a Y (C.l.E.)color value of 59.5.

For illustration purposes, the dyeability of the copolyester resinproducts prepared in the above examples were tested with cationic orbasic type dyestuffs. The numerical values given below under the nameCationic Dye Value were obtained by measuring the reflectance of thedyed resin with a Color-Eye" (model D-l which is the trade name for adif-v ferential colorimeter manufactured by the Instrument DevelopmentLaboratories, Attleboro, Mass. The color values obtained are based onluminance (Y in the CH5. System) which is a measure of the proportion ofthe incidence light reflected relative to a white vitrolite standardand, therefore, a measure of the whiteness of the copolyester resinproduct being evaluated. Based on a theoretically possible Y value of100, the higher the Y value, the whiter the resin product.Correspondingly, the lower the Y value or number, the more deep orintense the color of the dyed resin product. The determination of Y inthe C.|.E. System as set forth in the examples and hereinafter set forthwas carried out by using molded plaques of the polyester resin producthaving the dimensions l" l "X l/ l 6" which were prepared on a CarverPress.

The prepared molded plaques of the polyester resin samples to beevaluated for dyeability were then subjected to the following dyeingprocedures.

Cationic Dye Test A dye bath was prepared containing 1.25 g. Sevron BlueER, 10 g. Carolid 3F carrier, 12.5 g. Na SO and 225 mls. water. Thisbath was heated to l F. and the samples entered. The bath containing thesamples was raised to a boil over a -minute period and held at a boilfor another 60 minutes. Two scour baths were prepared containing 6.25mls. of a 1 percent lgepon T-Sl Solution, 3.1 mls. of a l percent Na,CO,solution, and 240 mls. water respectively. The samples were scoured inthese baths at 140 F. for IS minutes each and then air dried.

The copolyester resin product of example ll above when dyed according tothe above-described cationic dyeing procedure had a cationic dye valueor Y value of 9.7 A polyethylene terephthalate homoprepolymer preparedwith the same catalyst system and under the same conditions as examplell had a cationic dye value or Y value of 17.5.

Other copolyester resins are prepared from dimethyl terephthalate,ethylene glycol, and a minor amount of dibutyl2-hexyl-2-(p-sulfophenoxy) malonate, sodium salt, and in anotherinstance, a minor amount of dibutyl 2-propyl-2-(psulfophenoxy) malonate,sodium salt, by the same procedure as set forth above in examples I andll and the resulting copolyester resin products exhibit excellentcationic dye affinity.

Fibers were spun from the copolyester resin product of example ll andresulting fiber showed excellent dye affinity and retainability Theresults in the above example clearly show the novel and excellentresults achieved by the copolyester resins of the present inventionwhich are particularly well suited for filamentand film-formingpurposes.

The copolyester resin products of the present invention are consideredto be particularly desirable due to the fact that the primary esterunits comprising ethylene terephthalate and similar monomeric structuresneed only be modified to a slight degree with the other specifiedmodified ester units of the present invention to achieve the desiredresults.

We claim:

1. A cationic dyeable copolyester resin consisting essentially of thecondensation polymerization product of (a) an aromatic dicarboxylic acidor its lower alkyl diester, (b) a glycol selected from the groupconsisting of aliphatic glycols and cycloaliphatic glycols, and (c) aminor amount which is sufficient to impart cationic dyeability of asubstituted acid or ester thereof represented by the formula:

SOaM

wherein R and R are both hydrogen or lower alkyl radicals containingfrom one to four carbon atoms, R is hydrogen or a lower alkyl radicalcontaining from one to six carbon atoms, and M is a metal selected fromthe group consisting of alkaline earth metals and alkali metals.

2. A composition of claim 1 wherein (a) is terephthalic acid or a loweralkyl diester thereof.

3. A composition of claim 2 wherein (b) is ethylene glycol.

4. A composition of claim 1 wherein (a) is terephthalic acid or a loweralkyl diester thereof and a minor amount of another saturated aromaticdicarboxylic acid or lower alkyl diester thereof, (b) is a glycolrepresented by the formula: HO(CH ),0H, wherein z is a positive integerof from 2 to 6 and (c) is a substituted acid or ester thereofrepresented by the formula:

metals and alkaline earth metals.

5. A composition of claim I wherein (a) is terephthalic acid or a loweralkyl diester thereof, (b) is a mixture of a glycol represented by theformula: HO(CH,),OH, wherein z is a positive integer of from 2 to 6 anda minor amount of another glycol represented by the formula:

wherein a and b represent positive integers of from 1 to 3, R and Rrepresent lower alkyl radicals containing from one to six carbon atoms,and (c) is a substituted acid or ester thereof represented by theformula:

1 R100 CICOO CR2 0 wherein R and R, are both hydrogen or lower alkylradicals containing from one to four carbon atoms, R is hydrogen or alower alkyl radical containing from one to six carbon atoms, and M is ametal selected from the group consisting of alkaline earth metals andalkali metals.

6. A composition of claim I wherein (a) is dimethyl terephthalate, (b)is ethylene glycol, and (c) is the sodium salt ofdiethyl2-methyl-2-(p-sulfophenoxy) malonate.

7. A composition ofclaim 1 wherein (a) is terephthalic acid.

.(b) is ethylene glycol. and (c) is methyl-2-(p-sodiumsul' wherein z isa positive integer of from 2 to 6, R hydrogen or an alkyl radical havingfrom one to six carbon atoms and M is a metal selected from the groupconsisting of alkaline earth metals and alkali metals.

2. A composition of claim 1 wherein (a) is terephthalic acid or a loweralkyl diester thereof.
 3. A composition of claim 2 wherein (b) isethylene glycol.
 4. A composition of claim 1 wherein (a) is terephthalicacid or a lower alkyl diester thereof and a minor amount of anothersaturated aromatic dicarboxylic acid or lower alkyl diester thereof, (b)is a glycol represented by the formula: HO(CH2)zOH, wherein z is apositive integer of from 2 to 6 and (c) iS a substituted acid or esterthereof represented by the formula:
 5. A composition of claim 1 wherein(a) is terephthalic acid or a lower alkyl diester thereof, (b) is amixture of a glycol represented by the formula: HO(CH2)zOH, wherein z isa positive integer of from 2 to 6 and a minor amount of another glycolrepresented by the formula: wherein a and b represent positive integersof from 1 to 3, R4 and R5 represent lower alkyl radicals containing fromone to six carbon atoms, and (c) is a substituted acid or ester thereofrepresented by the formula:
 6. A composition of claim 1 wherein (a) isdimethyl terephthalate, (b) is ethylene glycol, and (c) is the sodiumsalt of diethyl 2-methyl-2-(p-sulfophenoxy) malonate.
 7. A compositionof claim 1 wherein (a) is terephthalic acid, (b) is ethylene glycol, and(c) is methyl-2-(p-sodiumsulfophenoxy) malonic acid.
 8. A composition ofclaim 1 wherein (a) is dimethyl terephthalate, (b) is ethylene glycol,and (c) is an alkali metal or alkaline earth metal salt of dimethyl2-ethyl-2-(p-sulfophenoxy) malonate.
 9. A composition of claim 8 wherein(c) is an alkali metal or alkaline earth metal salt of dimethyl2-(p-sulfophenoxy) malonate.
 10. A copolyester resin consistingessentially of a linear alkylene terephthalate polymer containing fromabout 0.5 to 10 mole percent of segments represented by the formula: